### Standards

**Newton’s laws predict the motion of most objects. As a basis for understanding this concept:**

- 1a. Students know how to solve problems that involve constant speed and average speed.
- 1b. Students know that when forces are balanced, no acceleration occurs; thus an object continues to move at a constant speed or stays at rest (Newton’s first law).
- 1c. Students know how to apply the law F = ma to solve one-dimensional motion problems that involve constant forces (Newton’s second law).
- 1d. Students know that when one object exerts a force on a second object, the second object always exerts a force of equal magnitude and in the opposite direction (Newton’s third law).
- 1e. Students know the relationship between the universal law of gravitation and the effect of gravity on an object at the surface of Earth.
- 1f. Students know applying a force to an object perpendicular to the direction of its motion causes the object to change direction but not speed (e.g., Earth’s gravitational force causes a satellite in a circular orbit to change direction but not speed).
- 1g. Students know circular motion requires the application of a constant force directed toward the center of the circle.
- 1h.* Students know Newton’s laws are not exact but provide very good approximations unless an object is moving close to the speed of light or is small enough that quantum effects are important.
- 1i.* Students know how to solve two-dimensional trajectory problems.
- 1j.* Students know how to resolve two-dimensional vectors into their components and calculate the magnitude and direction of a vector from its components.
- 1k.* Students know how to solve two-dimensional problems involving balanced forces (statics).
- 1l.* Students know how to solve problems in circular motion by using the formula for centripetal acceleration in the following form: a = v
^{2}/r. - 1m.* Students know how to solve problems involving the forces between two electric charges at a distance (Coulomb’s law) or the forces between two masses at a distance (universal gravitation).